This invention relates generally to dairy milker unit liners and more particularly to milker unit teat cup liners with internal flow diverters for distributing teat dip before a milker unit is detached from an animal being milked.
Milking machines are attached to dairy animals to withdraw and collect milk. The part of the milking machine that interfaces with the dairy animal includes an outer shell, called a teat cup, and an interior liner. A dairy animal's teat is inserted into a top opening in the teat cup and liner for milking. With vacuum hoses connected to these components, a pulsation is created that withdraws milk from the dairy animal's teat.
Liners are shaped and sized to maximize animal comfort, and to be efficient and responsive to the vacuum that causes pulsation. Liners have different designs, but all liners or liner assemblies have at least an upper dome and a barrel extending down from the dome. The liner components may be formed in a single unit or the dome and barrel may be separate pieces. The dome defines an opening through which a dairy animal's teat is inserted for milking. The dome also includes an outer skirt that fits down over the top of the teat cup to secure the two components together.
In addition to milking the animal, the vacuum also secures the teat cup and liner to the animal's teat during milking. When milking is completed, the vacuum is reduced so that the teat cup and liner are detached from the animal.
To maintain healthy animals and reduce the incidence of harmful mastitis, teats are treated with antimicrobial cleaners and sealants known as teat dips. These teat dips can be applied before milking or after milking depending on their primary purpose. Teat dips are usually applied by a dairy operator raising a hand-held cup full of teat dip into contact with the teat and possibly the lower udder or by spraying the teats with a hand-held wand.
To reduce manpower and improve animal throughput in a dairy, it is desirable to automate certain procedures normally performed by dairy operators. Applying a post-milking teat dip is one such operation that has been considered for automation.
Teat dip applicators incorporated into a milking machine apply dip to a cow's teat and possibly the lower portion of the udder just prior to detachment of the milking machine from the cow. Teat dip is injected with pumps or pushed with air pressure through nozzles or small orifices that are mounted on the corresponding teat cup or formed in the dome portion of the liner. (See for example: US 2006-0112886-A1.) Given size and time constraints, a single nozzle aimed at the teat applies teat dip to one side of the teat, but the opposite side is less likely to be covered unless a larger dosage of teat dip is injected.
Multiple nozzles have been proposed in an attempt to provide more uniform dip application than might be possible with a single nozzle. Multiple nozzles are fed by multiple tubes from a teat dip source or from a chamber formed in the liner dome. Given the confined nature of the liners within teat cup shells, tubes and chambers must be relatively small, and can be subject to clogging. Multiple nozzles also present increased manufacturing costs.
Another consideration in any such automated teat dip applicator is safety. Teat dips cannot be mixed with milk. Any system used to automatically apply a teat dip that is exposed to the inside of a milker unit liner also exposes the milk to a potential contaminant. As a result, the liner should be backflushed with water or cleansing solutions before the next animal is milked. Such backflushing is also most efficient and consistent if it is done automatically.
Thus, there is a need for an improved mode for delivering teat dip to upper portions of teats through automated dipping equipment.